Offload management
Introduction Offloading is the use of complementary network technologies(WiFi is the most popular) for delivering data originally targeted for cellular networks(3G, 4G).End users do data offloading for data service cost control and the availability of higher bandwidth. Operators do it to ease congestion of cellular networks. Since offload is related to improve performance of an operator network, hence proper management of policies and devices implementing those policies is of utmost importance. In this context 3GPP has already laid down some specifications related to mobile device management as a whole which also encompasses data traffic offload management in wireless mobile operator networks of the future. Key Components Management of data traffic(especially offloading) to mobile devices and the management of mobile devices as such have been standardized by 3GPP using 2 key components as described below - Access network discovery and selection function (ANDSF) conceived by 3GPP in Release 8 as part of the effort to standardise 3GPP compliant mobile devices like Smartphones, that can also access non-3GPP data networks. It is the most complete 3GPP approach to date for controlling offloading between 3GPP and non-3GPP access networks (such as WiFi). The purpose of the ANDSF is to help user devices to discover access networks in their vicinity and to provide policies to prioritize and manage connections to all networks. It is believed that NOCs in future will use nodes implementing ANDSF to manage mobile devices. 3GPP has also defined TS 24.312: access network discovery and selection function (ANDSF) management object (MO), to cater to mobile device management.It is expected that operator based traffic offloading configurations and management will be possible using ANDSF. OMA Device Management is a device management protocol specified by the Open Mobile Alliance (OMA) Device Management (DM) Working Group and the Data Synchronization (DS) Working Group. OMA DM specification is designed for management of mobile devices such as mobile phones, PDAs,and tablet computers. Device management is intended to support the following uses: * Provisioning – Configuration of the device (including first time use), enabling and disabling features * Device Configuration – Allow changes to settings and parameters of the device * Software Upgrades – Provide for new software and/or bug fixes to be loaded on the device, including applications and system software * Fault Management – Report errors from the device, query about status of device All of the above functions are supported by the OMA DM specification, and a device may optionally implement all or a subset of these features. Since OMA DM specification is aimed at mobile devices, it is designed to specifically cater to operate in devices having low memory and storage space, is constraint on bandwidth of communication and operates under tight security. ANDSF MO specified in TS 24.312 is compatible with the OMA Device Management (DM) protocol specifications, version 1.2 and upwards. Communication Protocol The OMA DM protocol unlike SNMP, uses XML for data exchange. The device management takes place by communication between a server (which is managing the device like the one implementing ANDSF) and the client (the device being managed like a smartphone). OMA DM is designed to support and utilize any number of data transports such as: * physically over both wireline (USB, RS-232) and wireless media (GSM, CDMA, IrDA, or Bluetooth) * transport layers implemented over any of WSP (WAP), HTTP, or OBEX or similar transports The communication protocol is a request-response protocol like SNMP. The server and client are both stateful.The communication is initiated by the OMA DM server, asynchronously, using any of the methods available such as a WAP Push or SMS. The initial message from server to client is said to be in the form of a notification, or alert message.Once the communication is established, a sequence of messages might be exchanged to complete a given device management task. OMA DM does provide for alerts, which are messages that can occur out of sequence, and can be initiated by either server or client. Such alerts are used to handle errors, abnormal terminations etc. Several parameters relating to the communication such as the maximum message size can be negotiated between the server and client during the initiation of a session. In order to transfer large objects, the protocol does allow for sending them in smaller chunks.Error recovery based on timeouts are not specified completely, hence, different implementations could possibly differ (protocol is not fully specified relating to these, and seem to leave them open intentionally). The protocol specifies exchange of Packages during a session, each package consisting of several messages, and each message in turn consisting of one or more commands. The server initiates the commands and the client is expected to execute the commands and return the result via a reply message. Conclusion The amount of traffic carried over WiFi networks has grown dramatically in recent years and is projected to continue to grow in the years to come.To address the issues related to growing data traffic demand, integration of Cellular and WiFi networks is the need of the hour which will facilitate evolution towards 5G mobile networks of the future. Along with the mechanisms to offload traffic, data traffic offload configurations and management is also gaining importance in the research community. It remains to be seen whether the key aspects of the above mentioned specifications are implemented as depicted or whether new more elegant mechanisms are implemented in future. References 3GPP Specs * TS 23.402 Architecture enhancements for non-3GPP accesses * TS 24.302 Access to the 3GPP evolved packet core (EPC) via non-3GPP access networks * TS 24.312 access network discovery and selection function (ANDSF) management object (MO)